SolidWorks 2010 Bible

Chapter 12: Building Efficient Assemblies

Organizing for performance

Performance in SolidWorks is a word used to mean speed. Subassemblies can contribute to speed-

saving modeling techniques by segmenting the work that the software needs to do at any one time.

Solving mates

The mates that contribute to putting the pieces of an assembly together are solved at the level of

the top assembly. Under normal circumstances, subassemblies are treated as static selections of

parts that are welded together, and their mates are not solved at the same time that the top-level

assemblies’ mates are solved. This segmenting of the mates leads to improved performance by only

solving one set of mates at a time.

Mates are usually solved as a single group unless there is a special situation, such as mates to

in-context features, component pattern instances, or an assembly feature, all of which have already

been described in this chapter. When one of these situations occurs, the mates have to be divided

into separate groups or solved multiple times. This is done transparently behind the scenes so that

the user does not have to worry about it. Multiple rebuilds affect the user only in terms of rebuild

times.

Flexible subassemblies

When you create subassemblies, the mates for the parts of the subassembly are not solved in the
upper-level assembly. This means that if a subassembly is a mechanism, the mechanism does not
allow Dynamic Assembly Motion in the upper-level assembly. For example, in Figure 12.7, the
front fork is a linkage mechanism, but it is also a subassembly. Without reassembling the parts of
the fork in the upper-level assembly, you can allow the mates from the fork subassembly to be
solved in the upper-level assembly by using the Flexible Subassembly option in the Component
Properties dialog box, which is also shown in Figure 12.7. When you select the Flexible option in
the Solve As section, you enable the mates of this subassembly to be solved in the upper-level
assembly, which allows the parts of the subassembly to move in the upper-level assembly.

To access the Component Properties dialog box, right-click the subassembly and select Component

Properties from the menu.

Flexible subassemblies have become more reliable and easier to use over the last several releases. I

encourage you to work with them or do some experimentation to see if they assist your modeling

process. If you find they cause trouble in some situations, they are easy enough to simply deactivate.

Legacy data

If you have assemblies that were built in older versions of SolidWorks (such as SolidWorks

2001+), mates used to be split up into multiple mate groups, which represented the groupings that

mates were solved in. This was forced by mating to the history-based features in the assembly

FeatureManager. SolidWorks no longer displays mate groups, but the groups are still used in the

background to solve mates. This is another change that SolidWorks has made to the software that

simplifies the user’s interaction with the software, but also makes it obvious that things are now

happening behind the scenes that you can’t control.